You only need two or three slots, some items like the chain thrower and laser pointer start burning things and breaking things so you need to think about when you put them in, but aside from that you can just fill up your chimney with infinte stuff until you run out of credits. No need to get extra spaces. Which is why by the end of the game Ihad that egg, the tomorrow corp ticket and a bunch of other things like the free hug still on my tray. That said, a lot of effort just for a short cutscene instead of an alternate ending where you get to go along.